For several years now, there has been a need for new parking places for pleasure boats or recreational boats. In the face of the unsatisfied demand for places in harbors, interest has been focused on solutions for storing boats on land, as alternative solutions complementary to floating ports, especially for the storage of small boats.
In general, there are two large classes of solutions for storing boats on land: dry docks and boat parks.
Dry docks offer pleasure-boat owners a service of storage on land and of launching of the boats when they request it, the operations being performed professionally, using specific, speedy and high-performance handling equipment (wharf fork-lift trucks, self-propelling hydraulic dolly on ramp, dock basin lift, cranes or mechanical boat lifts with removal on transporter trucks, systems with travelling cranes or carrier units, etc.). The boats are parked horizontally (for example on an open area (platform) or vertically (in metal structures in the form of racks on several levels (“boat racks”), outdoors or in shelters).
Boat parks are terrestrial spaces allocated permanently or seasonally to the parking of small boats launched by light handling means (tugs or trucks) most usually by the user himself, if the launching is done by using a ramp, or by means of heavier handling machines (jib cranes, power lift trucks or boat lifts) available on self-service or handled by the park manager if the launching is done from a wharf or quay.
We shall strive more particularly here below in the document to describe the problems and issues that the inventors of the present patent application have confronted and that exist when a dry dock type storage system for storing boats on land is implemented. As already mentioned further above, the invention is naturally not limited to this particular context of application but is of value in all cases where boats afloat have to be put on hold after they have been launched and/or before they are hauled out of water.
In a dry dock, a holding area for boats while afloat must imperatively be planned in proximity to the handling wharf (the wharf in which the handling machines used for launching boats or hauling them out of water are placed).
This place for keeping boats on hold when afloat has two symmetrical functions for the dry dock operator:                placing boats afloat on hold after they have been launched (i.e. the function of being able to launch boats in advance and keep them available for the pleasure-boat owners); and        placing boats afloat on hold before they are hauled out of the water (i.e. the function of making it possible to park the boats when they return and organizing the queue for the handling operations performed to return them to dry docks).        
In other words, the area for keeping boats on hold when afloat is aimed at reducing the bottlenecks constituted by the launching/hauling-out stations for boats and therefore at minimizing the waiting time of the pleasure-boat owners and meeting demand and the requirements of busy periods as efficiently as possible. It also enables secure removal or return of boats that is independent of the handling and storage areas.
Classically, the holding area comprises a holding wharf or a holding pontoon or floating dock. Its size depends for example on the capacity of the dry dock, the rate at which the boats exit during peak times and the speed of the handling operations.
The presently used technique for placing boats on hold (the holding wharf or holding pontoon) is not optimal and has several drawbacks, especially:                the capacity of putting boats on hold (i.e. the number of boats that can be put on hold) is limited, unless the length of the holding wharf or the holding pontoon is increased, which is not desirable since this amounts to increasing the occupancy of the seafront (i.e. more generally restricting the possibilities of access to the water body as defined here above);        at peak hours, the user must wait for the boat to be made available and for it to be taken into account for storage;        the action by the pleasure-boat owner and/or the staff of the port is necessary during operations for moving the boat to or from the holding area: on the one hand after the boat has been launched to bring it from a launching position to a receiving position in the holding area and to moor it and on the other hand before the boat been hauled out of the water to unmoor it and bring it to a reception place in the holding area up to a hauling-out position;        there is a need to secure the boats during these operations for moving the boat to or from the holding area as well as during periods of being on hold when afloat, in the waiting area.        